In light-emitting structures, indium gallium nitride quantum wells (hereinafter “InGaN quantum wells”) are separated by (In)GaN barrier layers. The heterojunction between the quantum wells and the barrier layers forms a potential barrier, which impedes the injection of charge carriers, i.e. of electrons and holes. The potential barriers formed by the heterojunctions arise as a result of the high piezoelectric fields between the quantum wells and the barrier layers. Since the number of heterojunctions increases with the number of quantum wells, it is difficult to construct a light-emitting structure that contains a plurality of quantum wells.